1. Field of the Invention
This invention relates to a high strength grouted pipe coupler by which either a pair of spaced, axially aligned steel reinforcing bars (i.e. rebars) are reliably spliced to one another or a single reinforcement bar is reliably anchored to a flat steel plate to form a T-headed bar configuration for the purpose of connecting together and providing continuous support for precast or cast-in-place concrete structures to be better able to withstand a seismic event.
2. Background Art
It is common in the construction industry, during the erection and retrofitting of buildings, parking structures, bridges, subways, airports, etc., to add a new contiguous concrete structure to an existing concrete structure. Care must be taken during construction to ensure that the contiguous structures are interconnected so that they will not shift relative to one another, particularly as a consequence of a seismic event. The foregoing has been reliably accomplished by the high strength grouted pipe coupler described in my earlier U.S. Pat. No. 6,192,647 issued Feb. 27, 2001. The pipe coupler therein disclosed splices together a pair of reinforcement bars that are axially aligned one above the other within a cylindrical pipe or tube. The opposing ends of the pair of axially aligned reinforcement bars that are surrounded by the coupler tube are headed. That is, each reinforcement bar has a relatively wide upset heard formed at an end thereof. One of the upset heads is mated to a threaded collar. The threaded collar is, in turn, mated to the coupler tube at a threaded interior portion thereof.
The relatively wide upset heads of the pair of reinforcement bars to be spliced together necessities that the coupler tube have a relatively large diameter. Accordingly, a relatively large amount of cement grout is required to fill the coupler tube to form a solid core within which the reinforcement bars will be embedded. In addition to the formation of the upset heads, the threaded collar and the threaded portion of the coupler tube to which the collar is mated increases manufacturing costs and time, particularly in cases where a large number of reinforcement bar couplers are needed at a job site. Therefore, it would be desirable to be able to manufacture a reliable high strength pipe coupler like that described in my U.S. Pat. No. 6,192,647, but which is more compact in construction, is less costly to manufacture, and requires less grout to fill.
According to a first embodiment of this invention, a high strength grouted pipe coupler is disclosed by which pairs of spaced, axially aligned steel reinforcement bars (i.e. rebars) are spliced to one another for connecting together contiguous precast and cast-in-place columns walls, beams, etc. during the construction or retrofitting of a building, parking garage, bridge, subway, airport, or the like. A concrete structure has a first reinforcement bar embedded therewithin and projecting outwardly therefrom. A cylindrical steel sleeve or tube is positioned around the free end of the first reinforcement bar. A second reinforcement bar is inserted through the top of the coupler tube so as to be positioned in vertical axial alignment with the first bar. A spirally wound reinforcing spring is disposed in a bore between the first and second axially aligned reinforcement bars and the coupler tube for surrounding the opposing ends of the reinforcement bars to be spliced together. A removable stopper pin is then inserted through an inlet opening in the coupler tube so as to extend between the opposing ends of the first and second axially aligned reinforcement bars to establish a gap therebetween. Next, a pair of set screws are inserted through screw holes formed in the top and bottom ends of the coupler tube in order to maintain the positions of the pair of reinforcement bars. With the set screws moved into locking engagement with respective reinforcing bars, the stopper pin is removed, and a supply of epoxy or cement based grout fills the coupler bore via the inlet opening from which the stopper pin has been removed. When the epoxy or grout hardens, a solid core is formed at the interior of the coupler tube by which to reliably couple the pair of reinforcement bars in spaced end-to-end vertical alignment.
According to a second embodiment of this invention, a cylindrical sleeve or tube is affixed (e.g. friction welded) to a flat steel plate. A single reinforcement bar is inserted through the coupler tube so as to rest against the flat plate. A spirally wound reinforcing spring is disposed in a bore between the reinforcement bar and the coupler tube so as to surround the bar to be coupled to the plate. The reinforcement bar is then lifted a short distance off the plate and a set screw is inserted through a screw hole formed in the top end of the coupler tube in order to maintain the position of the reinforcement bar relative to the plate lying therebelow. With the set screw moved into locking engagement with the reinforcement bar, a supply of epoxy or cement based grout fills the coupler bore via an inlet opening at the bottom end of the coupler tube. When the epoxy or grout hardens, a solid core is formed at the interior of the coupler tube to reliably couple the single reinforcement bar in spaced alignment to the flat plate to create a high performance T-headed bar.